Analysis of cancers missed at screening mammography.

Analysis of 320 cancers found in a screened population between August 1985 and May 1990 revealed 77 cancers that were "missed" at screening mammography. The missed lesions consisted of cancers incorrectly diagnosed after mammography (false-negative results) but visible in retrospect (n = 19); cancers correctly diagnosed after mammography but visible in retrospect on an earlier mammogram (n = 47); and cancers that went undetected by the first of two readers (n = 11). Missed lesions were categorized according to type of miss, reason for the miss, breast density, lesion features, and lesion location. The missed lesion were compared with 121 cancers that were correctly diagnosed at screening mammography. The missed cancers occurred in women with denser breasts (P = .046), were less likely to demonstrate malignant microcalcifications, and were more likely to demonstrate a developing opacity as an indication of cancer (P = .005). An understanding of the characteristics of missed lesions may be a valuable aid in increasing the sensitivity of screening mammography.     

Unconscious perception of "extinguished" visual stimuli: reassessing the evidence.

When parietal-damaged patients fail to report a contralesional stimulus because of extinction, is this because the stimulus is not perceived, or because it is perceived but cannot reach conscious awareness? VOLPE et al. [10] reported an intriguing study that seemed to locate the problem at least partly in the transfer of information to conscious awareness. They showed patients with extinction pairs of stimuli, one in each hemifield. Although patients were predictably poor at reporting the identity of the contralesional stimulus, they were able to make accurate same/different judgements comparing the two stimuli. This was interpreted as evidence that both stimuli were perceived. In the present paper, we point out that the dissociation between identification and same/different matching could also be due to the possibility that less visual information about the contralesional stimulus is necessary to make a same/different judgement than to identify the stimulus, and that chance performance is considerably higher in the first than in the second type of task. In Experiment 1, we verified this by degrading one side of a stimulus display and "replicating" the dissociation with normal subjects. We also equated the amount of visual information needed for the two tasks by yoking the stimulus pairs on "different" trials of the same/different matching task with the choice pairs on a forced choice identification task. Under these conditions, the dissociation vanished. In Experiment 2, we administered these tasks to three parietal-damaged patients with extinction. When the original method was used, same/different matching was better than identification of the contralesional stimulus. With the forced choice identification method, the dissociation again vanished.     

Tricuspid valve prosthetic replacement. Early and late results with the Starr-Edwards prosthesis.

The total experience (154 patients) with ball-valve (Starr-Edwards) replacement of the tricuspid valve, alone and in combination, through Dec. 31, 1971, at the Mayo Clinic is reviewed. The early mortality rate with isolated tricuspid replacement was twice that for tricuspid replacement combined with replacement of other valves. Among patients receiving three valves, those with "functional' tricuspid insufficiency and those who were in New York Heart Association (N.Y.H.A.) Class IV preoperatively had a higher early mortality rate. The early mortality rate for the total group was 28%. Of those surviving tricuspid plus mitral valve replacement, 70% were alive at 3 years; at latest follow-up, 94% of those surviving were functionally improved. Of those surviving triple valve replacement, 56% were alive at 3 years; at latest follow-up, 93% of those surviving were functionally improved. Previous cardiac surgery with residual tricuspid valve dysfunction and severe disability, as judged by N.Y.H.A. class, influenced the outcome adversely. The experience reported here provides a standard against which never prostheses can be compared.     

A major gene controlling warfarin-resistance in the house mouse.

The spread of a "cream" mutant in a wild population of house mice is reported. The hypothesis that the gene responsible for the colour, extreme chinchilla, ce, has spread because of linkage with a major gene for warfarin-resistance, is tested by a linkage backcross. The results prove that a major gene does exist, that it is very closely linked with frizzy, fr, in chromosome 7, which in turn is linked with ce, that it is fully dominant in females at 4 months of age, and that its partial dominance in males is under the control of modifiers. The symbol War is proposed for the gene. Its position in chromosome 7 is analagous with the position of the resistant gene, Rw2, in the rat in the analagous chromosome. The adaptive significance of the finding is discussed, as also are reports of certain other mutants in wild populations of mice.     

Mitochondrial DNA sequence diversity in bipolar affective disorder

OBJECTIVE: Point mutations in mitochondrial DNA (mtDNA) are one mechanism that could explain the apparent excess maternal transmission of bipolar affective disorder observed in some families. The authors sequenced the mtDNA from probands with bipolar disorder and tested nucleotide variants for association with the disorder. METHOD: The entire 16.5 kilobase mitochondrial genome was sequenced in nine unrelated probands selected from large pedigrees with exclusively maternal transmission of bipolar affective disorder. Compared to a reference sequence, variants were detected at 107 nucleotide positions. Fifteen variants of possible pathogenic significance were selected for further study. These variants were assayed in 93 unrelated probands with bipolar I, bipolar II, or schizoaffective-manic disorder and 63 comparison subjects, all of whom were classified into the major groups comprising the European mtDNA haplotype structure (haplogroups).RESULTS: The major European haplogroups were represented at the expected frequencies among both probands and comparison subjects. There was no significant difference between probands and comparison subjects in the frequency of any variant, although odds ratios >2 or <0.5 were observed for four variants. Frequencies of these four variants were similar in probands and haplogroup-matched comparison subjects. The results of all comparisons were essentially unchanged when probands from families with an apparently paternal transmission pattern were excluded.CONCLUSIONS: The results demonstrate that bipolar affective disorder occurs across all of the major European mtDNA haplogroups but do not reveal any point mutations that explain excess maternal transmission of the disorder.